Embodiments of the present invention relate to a semiconductor device including a capacitor and a method for manufacturing the same, and more particularly to a semiconductor device and a method for manufacturing the same, which can more effectively prevent a storage node of a capacitor from leaning and can increase a contact region between a storage node and a contact plug.
Generally, semiconductor devices for memory such as a Dynamic Random Access Memory (DRAM) have been designed to retain information such as data or program instructions.
Typically, a unit cell storing data includes one transistor and one capacitor. A capacitor contained in a DRAM element or the like includes a storage node, a dielectric layer, and a plate electrode.
In recent times, with the increasing integration of the semiconductor device, an allowable area per unit cell is reduced, such that many developers and companies are conducting research into various technologies capable of making a capacitor that occupies less surface area on a substrate.
A variety of methods have been used to increase capacitance, for example, a method for employing a dielectric layer having a high dielectric constant, a method for forming a storage node and a plate electrode that are formed of a metal layer having a high work function, and a method for increasing a surface area of the capacitor.
In order to enlarge the surface area of the capacitor, the height of a storage node needs to be increased. That is, in a semiconductor device to which precise critical dimension (CD) technology is applied, in order to assign capacitance requested by the capacitor within an allowed cell region, an aspect ratio of the capacitor needs to be increased. However, provided that the aspect ratio of the capacitor is increased, the number of leaning defects in a capacitor array may be increased, such that there is a high possibility of causing a bridge between neighboring storage nodes.
In addition, the conventional storage node formation method forms an interlayer insulation film, forms a storage node contact hole by etching a region in which the storage node is to be formed, and deposits an electrode material in the contact hole. However, the above-mentioned conventional storage node formation method has some problems. In more detail, if the aspect ratio of the contact hole is increased, it is difficult to etch lower portions of the hole. In addition, a contact region of the contact plug may be smaller than desired, possibly resulting in increased resistance.